Some of my frends are going to Nepal in early september . I contemplate joining them. But i am not sure about weather conditions at this time . Has anyone been to Nepal in september? Could anyone give me some advice on this?

I spent a month in Langtang valley in April/May 1996. Too much snow. The locals said September was the best month. But they're not going trekking or climbing. I would say early Sept is too early, particularly as the walk-in is low, not like Everest or Mustang. From mid-Sept onwards might be OK, and Oct is considered best. Walking out in early May was humid, muddy and leeches. I assume early Sept would be the same. Only upside is it's such an accessible trek you're only in the mud a couple of days. Once above Langtang village you should be fine, around 3000m. KTM late August is hot, humid and dirty.

i've done the annapurna circuit in late september/early october. the weather was pretty ideal. pretty warm and humid down low but very mild and temperate at higher elevations. clear skies, not a drop of rain, and not too cold at night. might have dipped a little below freezing at the highest points on the trek.

I trekked around Annapurna and into the Annapurna Sanctuary in September of 2001. If I were you, I wouldn't hesitate to go. The mountain views probably won't be as good as you'd get in October or November, but they'll still be good. I hardly saw any rain. Plus, there are some other bonuses - you'll be just ahead of the main trekking season, which means the trails will be less crowded, all the inns will be full of supplies, and you'll get to spend the night wherever you want.